华东师范大学学报（自然科学版） ›› 2022, Vol. 2022 ›› Issue (2): 127-134.doi: 10.3969/j.issn.1000-5641.2022.02.015

• 物理学与电子学 • 上一篇    下一篇

双色光绝热冷却原子数值优化的研究

钱晨扬, 董光炯*()   

  1. 华东师范大学 精密光谱科学与技术国家重点实验室, 上海　200241
  • 收稿日期:2021-04-13 出版日期:2022-03-25 发布日期:2022-03-28
  • 通讯作者: 董光炯 E-mail:gjdong@phy.ecnu.edu.cn

Numerical optimization of bichromatic adiabatic cooling

Chenyang QIAN, Guangjiong DONG*()   

  1. State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai　200214, China
  • Received:2021-04-13 Online:2022-03-25 Published:2022-03-28
  • Contact: Guangjiong DONG E-mail:gjdong@phy.ecnu.edu.cn

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摘要：

双色光绝热冷却原子方法是近年来发展出的一种不需要依靠自发辐射的激光冷却方法, 然而效率不高. 通过数值模拟方法优化了双色光绝热冷却的过程, 发现存在最佳的双色光场脉冲时间从而获得最佳冷却效果; 比较了使用高斯光脉冲和方脉冲这两种脉冲的冷却效果, 发现脉冲形式对冷却效果无显著影响. 由于该数值模拟方法依赖于光场-原子系统的绝热演化, 数值研究表明, 降低原子束的速度能够提高冷却效果. 最后研究了自发辐射对双色光绝热的影响, 发现在脉冲时间较长时自发辐射会降低冷却效果.

关键词: 双色光绝热冷却, 冷原子, 光力

Abstract:

In recent years, a new laser cooling method—named bichromatic adiabatic cooling—has been developed; however, the method offers low cooling efficiency. In this paper, numerical optimization of the bichromatic adiabatic cooling process has been performed. It is shown that there is an optimal pulse time for the optical fields to achieve the highest cooling efficiency. Moreover, a comparison of the cooling efficiency with the Gaussian light pulse and square pulse shows that the cooling efficiency is insensitive to the pulse shape. Because this cooling method relies on adiabatic evolution of the light field-atom system, it is shown that it is better to slow the speed of the atomic beam to maintain the adiabatic condition. Finally, the effect of spontaneous emission on bichromatic adiabatic cooling is studied. The results show that use of a long pulse significantly reduces cooling efficiency.

Key words: bichromatic adiabatic cooling, cold atom, optical force

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